Rubber composition and method of preserving rubber



Patented Dec. 26, 1933 RUBBER, COMPOSITION I .PREsERVING RUBBER ArthurW.,Sloan, Akron, Ohio, assignor to The i B. F. Go'odrichCompany, New ncorporation ofNew York No Drawing. Application March 7, :-Serial No.-521,010..

York, N. Y., a

' 38 Claims; (oils-50 This invention relates totheart of rubbermanufacture, and particularly tothe preparation of rubber compositionswhich resist the deterioration due to aging or to exposure to the attwoor more aromatic ring structures-attached. to a central aliphaticnucleus. These compounds may, if desired, contain other basic or"neutral substituents including the radicals offethers, al-

cohols, primary and tertiary amines, etc;, but strongly acidicsubsti'tuentgroups such 'as car-' boxyl or sulphonic acid groups whichhye" the effect of greatly retarding" vulcanization, and other groupscontaining doubly bound oxygen; nitrogen, sulphur, or other inorganicelements, should in general be avoidedbecause of their re-, duced'oreven negative anti-oxidant power or because of their undesirably strongeiTect on the vulcanization of the rubber.

For example, the following substances are typical members ofthe class-ofsubstances outlined above: p-phenylamino tetraphenyl methane, tolylp-amino tetraphenylmethane, naphthyl p-amino tetraphenylmethane,p-biphenyl p-amino tetraphenylmethane, p-phenylamino phenyl tritolylmethane, p-phenylamino phenyl tri-biphenyl methane, biphenyl-aminotetrabiphenyl methane, p-phenylamino phenyl trianisyl methane,p-phenylamino phenyltrinaph thyl methane, p naphthylamino phenyltrinaphthyl methane, p-benzylamino tetraphenylmethane, p-isopropylaminotetraphenylmethane, diphenyl p, p diamino diphenyl dimethyljmethane,

triphenyl triamino triphenyl methane, diphenyl diamino diphenylcarbinol, p-phenylamino p'dimethylamino "diphenylmefthane, p -phenylamino p'amino diphenylmethane, dinaphthyldi amino diphenylmethane,mononaphthyl diamino diphenylmethane, diphenyl diamino diphenylmethane,diphenyl diamino triphenylmethane, dibenzyl diamino diphenylmethane,diethyl di'- amino. diphenyl methane, p, p. di-triphenylmethyldiphenylethylene diamine, diphenyl p, p' diamino dibenzyl,p-triphenylmethyl pphenylamino diphenylamine, -p'-phenylamino phenylxylyl methane, triphenylmethyl paminotetraphenylmethanaetc. I Thecompoundsenume'rated above are readily -UNITEDSTATES PATENT, oFFmprepared from inexpensive raw materials by the usual reactionsfamiliar'tjo organic chemists. .For example, the diaryl diamino'dephe'nyl methane compoundsare readily prepared by condensing anilinehydrochloride first with formaldehyde and then with 'a phenolor anaromatic amine. Thesecondary amino tetra-aryl methane compounds aremostreadily prepared by condensing'a triaryl methyl chloride with adiarylamine; although the primary amine-may be prepared first, ifdesired, by reacting the triaryl methyl chloride with anilinehydrochloride, the product being then further reacted with a phenol oramine to give the desired secondary amine. I. j .Any one or a mixture ofseveralof thejaboveenumerated substances or of these substances withother known anti-oxidants may be incorporated into rubber'fwith goodeffect on. its age,-

resi'sting properties. For ex'ampleirom to 5% of suchan anti-oxidantmaybe mixed .with the rubber. before yulcanization, the anti-oxidant havingsubstantially no accelerating effect and therefore ordinarily. notnecessitating an adjustment of vulcanizingiconditi'ons. Alternately theanti-oxidant may be applied to the surface; of crude or vulcanizedrubber, say in the form, of a powder, paste, or solution. Rubber sotreated resists the deteriorating influence of age and exposure to theelements far better than similar 1111-, treatedrubber.

Example 1.As a specific example of one em; bodiment of the methodof thisinvention, a typi-' cal tire tread compositionwas' prepared containing:blended plantation rubbers approximately 100 partfby'weight, sulfur 5.5parts, zinc oxide 30parts, gas black 40 parts, mineral rubber'lfl parts,palm oil 5 parts, and hexamethylene tetra mine 0.75 parts. This wasdivided into portions, one of which was used as a control. Toeach oi theothers was added 095 parts (0.5% of the weight of the composition) ofone of theabovedescribed anti-oxidants; The compositions were thoroughlymixed, and vulcanized in a press for 45 minutes at145" '0. (294 F.) toproduce an op: timum cure. The relative rates of aging of the'Acceleratedaging tests were carried out in thevulcanized compositionswere compared by'meas- G eer. aging oven, in which sampleswere maintained at a temperature of 70C. (158 F.) "in aconstantly'renewed'streamof air, as well'as in the Bierer-Davis bomb, inwhich other samples were maintained at the same temperature C.) in anatmosphere of oxygen at a pressure of 300 lbs. per sq. in. The resultsof the tests are given in the table below. in which T indicates ultimateelongation in per cent. of original length.

Aging tests f 7 gifts! 4s .1 4 .1 1 ours in g days in the Bierer- 1 gGeer oven Davis Anti-oxidant bomb T E 'l E T None (control) 3,520 @33'1,920 5153 153 2 97 p-naphthylamino p-am ino diphenyl methane 3,710 6372,460 400 2,060 495 dinaphthyl diamino diphenyl methane 3, 790 660 2,500607 2; 130 555 E'wampZe 2.Another rubber composition was prepared andtested as indicated in Example 1 above, except that p-phenylaminotetraphenyl- It is evident from the above examples that rubbercompositions containing even small proportions of the anti-oxidants ofthis invention resist deterioration far more effectively than similaruntreated compositions. Not only are they outstandingly eificientanti-oxidants,'but they do not discolor the rubber goods upon exposureto sunlight, as do all other known classesojf efiective age-resisters.

Obviously, the practice or" this invention is not limited tothe's'pecific compositions given above, such compositions being merelyillustrative of one manner of employing the anti-oxidants of thisinvention. The anti-oxidants mayv beem ployed in conjunction with othervulcanizing agents than those here specifically disclosed, for

this invention is applicable generally to pure rubber or rubbercompositions of the most varied nature. Certain of them, particularlythe tetraaryl methane compounds, are exceptionally valuable for use inconnection with the so-called acid cure because of their comparativeinertness with respect to sulphur chloride.

It is to beunderstood that the term treating as employed in the appendedclaims is used in a generic sense to include either the incorpora tionof the anti-oxidants into the rubber by milling or similar process, ortheir addition to the rubber latex before the coagulation, or to theapplication thereof to the surface of a mass of crude or vulcanizedrubber. The term rubber is likewise employed in the claims in a genericsenseto include caoutchouc, whethernaturalor synthetic, reclaimedrubber, balata, guttapercha, rubber isomers and like products, whetheror not admixed with fillers, pigments, vulcanizing or acceleratingagents. 7

While I have herein disclosed certain preferred manners of performing myinvention, 1 do not thereby desire or'intendto limitmyself solelythereto, for, as hitherto stated, the precise proportions of thematerials utilized may be varied and other materials having equivalentchemical properties may be employed if desired without departing fromthe spirit and scope of the invention as defined in the appended claims.

This application is a continuation in part of my copending application,Serial No. 301,423, filed August 22, 1928.

Iclaimf M 1. The'method of preserving rubber which comprises treatingrubber with a secondary amino derivative of a hydrocarbon containing atleast two aromatic ring structures attached to a central aliphaticnucleus.

2. The method of preservingrubber which con1- prises treating rubberwith a secondary amino derivative of a poly-aryl methane.

3. The method of preserving rubber which comr s treating ubb r w h asecondary arylamino derivative of a poly-'aryl methane.

l 4. The method of; preserving rubber which corn-v prises treatingrubber with a secondary amino diphenylmethane. 1

5. The method of preserving rubber which com prises treating rubber witha secondary aromatic derivative of a diamino diarylmethane.

6. The method of preserving rubber which come prises treating rubberwith a naphthylamino di phenylmethane. r

7. The method of preserving rubber which comprises treating rubber witha secondary amino tetra-aryl methane.

8. The method of preserving rubber which com phenyl methane. a

9. The method of preserving rubber which cornprises vulcanizing. rubberin the presence of a secondary amino poly-aryl methane. v

.10. A composition of matter comprising-rubber and a secondary aminoderivative of a hydroe carbon containing at least two aromatic ringstructures attached to a central aliphatic nucleus.

11. A composition of matter comprising rubber and a secondary aminoderivativeof apolyaryl methane. i V

'12. A composition of matter comprising rub-J ber and a secondaryarylamino derivative or a poly-aryl methane. i V i 13. A composition ofmatter. comprising rubber and a secondary aminodiphenyl methane.

14. A composition of matter comprising rubprises treating rubber with anarylamino tetra ber and a naphthylamino diphenyl methane.

15., A composition of matter comprising rubber and a secondary aminotetra-aryl methane.

16. A composition of matter comprising rub ber and an arylaminotetraphenyl methanej 17. A composition of matter comprisingrub,- berwhich has been vulcanized in the. presence of a secondary aminopoly-aryl'methane, 18. The process of manufacturing a vulcanized rubberproduct possessing "age resisting char acteristics which comprisesincorporating with said product prior to vulcanization a reactionproduct of a hydroxy substituted aromatic hydrocarbon anddiaminoediphenyl-methane.

19. The process of manufacturing a vulcanized rubber product possessingage resisting characteristics which comprises incorporating. with saidproduct prior to vulcanization a reaction product of a naphthol anddiamino-diphenylmethane. I

20. The process of manufacturing a vulcanized rubber product possessingage resisting character istics which comprises incorporating with saidproduct prior to vulcanization a reaction product of substantially twomolar portions of beta naphthol and substantially one molar portion ofdiamino-diphenyl-methane.

21. The method of preserving rubber which comprises treating rubber witha beta naphthylamino diaryl methane.

22. The method of preserving rubber which comprises treating rubber witha diaryl diamino.

diaryl methane.

23. The method of preserving rubber which comprises treating rubber witha naphthylamino poly-aryl methane. l

24. The method of preserving rubber which wherein A and A representamino groups, at least comprises treating rubber with aphenylaminopoly-aryl methane.

25. The method of preserving rubber which comprises treating rubber withan 'arylamin tetra-aryl methane.

26. The method ofpreserving rubber which comprises treating rubber withphenylamino tetraphenylmethane.

2'7. The method of preserving rubber which comprises treating rubberwith beta dinaphthyl diamino diphenylmethane.

28. The method of preserving rubber which comprises treating rubber withdiphenyl diamino diphenylmethane.

29. A composition of matter comprising rubber and a naphthylaminopoly-aryl methane.

30. A composition of matter comprising rubber and a'beta naphthylaminodiarylmethane.

31. A composition of matter comprising rubber and a diaryl diaminodiaryl methane.

32. A composition of matter comprising rubber and an arylaminotetra-aryl methane.

33. A composition of matter comprising rubber and a phenylaminopoly-aryl methane.

34. A composition of matter comprising rubber and-phenylaminotetraphenylmethane.

35. A composition of matter comprising rubber and diphenyl diaminodiphenylmethane.

36. A composition of matter comprising rubber andbeta dinaphthyl diaminodiphenylmethane.

37. The method of preserving rubber which comprises treating rubber witha substance having the general formula carbon substituent, R and Rrepresent phenyl groups or substituted phenyl groups, and X and Yrepresent H or an alkyl or aryl hydrocarbon substituent. I 7

' ARTHUR W. SLOAN.

